Children's Mercy Hospitals and Clinics
Name
Cytogenetics- Microarray DNA analysis

CMH Lab Section
Cytogenetics

Clinical Description
Microarray-based Comparative Genomic Hybridization (aCGH) or DNA microarray is a whole genome scanning method. In one single assay, the entire genome is evaluated for gains and/or losses of genomic regions as well as chromosomal aneuploidy. Indications for postnatal aCGH testing include:
  • Failure to thrive (FOT)
  • Developmental Delay (DD)
  • Mental retardation (MR)
  • Multiple congenital anomaly (MCA)
  • Dysmorphic features (DF)
  • Autism or autism spectrum disorders (ASD)
  • Congenital heart diseases (CHD)
  • Seizures
  • Learning disability
  • Abnormal MRI/CT findings
  • Muscular dystrophy
  • Infertility


Specimen Requirements
2-3 mL blood in EDTA lavender tube

Availability
Routine

Turn Around Time
Two (2) weeks for normal or preliminary abnormal results; three (3) weeks for confirmed abnormal results; and two (2) weeks for parental checking.

Methodology
aCGH tests are performed using Agilent Human Genome Microarray Kit 244K (aCGH-244K). Quantitative real-time PCR (qPCR) technique is the primary method for the confirmation of abnormal copy number variants (CNVs) in patients and parental follow-up studies. FISH or chromosome GTG banding analyses will be recommended if a translocation is suspected.

Limitations: The Agilent aCGH-244K will not detect the following genomic abnormalities:
  • Balanced chromosomal aberrations, such as balanced translocations;
  • inversions or balanced insertions;
  • Point mutations and genomic imbalances in regions that are not represented on the microarray;
  • Low-level moasicism;
  • Polyploidy


Ranges
Each result report will have a brief description of aCGH finding. If an abnormal aCGH result is identified, a confirmation result, summarized interpretation, comprehensive comments, useful recommendation and related references will be provided.

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